SOD2 and cancer: In stratified analysis by cancer type, our results showed evidence that SOD2 V16A polymorphism is significantly associated with increased risk of prostate cancer (A-allele vs. V-allele: OR = 1.07, 95% CI = 1.00 – 1.15, Pheterogeneity = 0.047, P = 0.043, Figure 2; AA+AV vs. VV: OR = 1.12, 95% CI = 1.04 – 1.20, Pheterogeneity = 0.470, P = 0.003), but not for bladder cancer (A-allele vs. V-allele: OR = 1.01, 95% CI = 0.93 – 1.09, Pheterogeneity = 0.089, P = 0.892, Figure 2; AA+AV vs. VV: OR = 1.12, 95% CI = 1.04 – 1.20, Pheterogeneity = 0.470, P = 0.003).